1. Field of the Invention
The present invention relates to a mute apparatus for muting and unmuting an audio signal and a mute method of operating the mute apparatus, and more particularly to a mute apparatus having a plurality of mute switches.
2. Description of the Related Art
As a mute apparatus of this type, there have so far been proposed a wide variety of mute apparatuses having a plurality of mute switches for muting and unmuting an audio signal. This type of the mute apparatus generally comprises an input terminal, an output terminal, a plurality of mute switch control means, a plurality of mute switch control data generating means, and a plurality of mute switches. The mute apparatus is utilized for muting and unmuting an input audio signal to output a muted or unmuted audio signal.
FIG. 9 shows a conventional mute apparatus 900 having three mute switches. The number of mute switches may be changed depending on the mute apparatus in use. The conventional mute apparatus 900 comprises an input terminal 1, an output terminal 2, first mute switch control means 24, second mute switch control means 25, third mute switch control means 26, first mute switch control data generating means 27, second mute switch control data generating means 28, third mute switch control data generating means 29, a first mute switch 71, a second mute switch 72, and a third mute switch 73.
The input terminal 1 is adapted to input an audio signal and output the audio signal to the first mute switch control means 24. The first mute switch 71 is adapted to selectively assume two operation states consisting of mute-on and mute-off states. The second mute switch 72 is adapted to selectively assume two operation states consisting of mute-on and mute-off states. The third mute switch 73 is adapted to selectively assume two operation states consisting of mute-on and mute-off states. The first mute switch control means 24 is adapted to selectively assume two execution states consisting of mute-on and mute-off states to selectively mute and unmute the audio signal inputted by the input terminal 1 and output a muted or unmuted audio signal to the second mute switch control means 25. The second mute switch control means 25 is adapted to selectively assume two execution states consisting of mute-on and mute off states to selectively mute and unmute the muted or unmuted audio signal outputted by the first mute switch control means 24 and output a muted or unmuted audio signal to the third mute switch control means 26. The third mute switch control means 26 is adapted to selectively assume two execution states consisting of mute-on and mute-off states to selectively mute and unmute the muted or unmuted audio signal outputted by the second mute switch control means 25 and output a muted or unmuted audio signal to the output terminal 2. The output terminal 2 is adapted to output the muted or unmuted audio signal outputted by the third mute switch control means 26.
The first mute switch control data generating means 27 is adapted to generate a first mute switch control data element indicative of the operation state of the first mute switch 71, and the first mute switch control means 24 is adapted to assume the mute-on state or mute-off state on the basis of the first mute switch control data element. The second mute switch control data generating means 28 is adapted to generate a second mute switch control data element indicative of the operation state of the second mute switch 72, and the second mute switch control means 25 is adapted to assume the mute-on state or mute-off state on the basis of the second mute switch control data element. The third mute switch control data generating means 29 is adapted to generate a third mute switch control data element indicative of the operation state of the third mute switch 73, and the third mute switch control means 26 is adapted to assume the mute-on or mute-off state on the basis of the third mute switch control data element.
The operation of the conventional mute apparatus 900 will be described hereinlater.
As shown in FIG. 9, the first input terminal 1 is firstly operated to input an audio signal, and output the audio signal to the first mute switch control means 24. The first mute switch control means 24 is then operated to mute the audio signal inputted by the input terminal 1 and output the muted audio signal to the second mute switch control means 25 when the first mute switch control data generating means 27 is operated to generate a first mute switch control data element indicative of the mute-on state of the first mute switch 71. The first mute switch control means 24 is operated to unmute the audio signal inputted by the input terminal 1 and output the audio signal to the second mute switch control means 25 when the first mute switch control data generating means 27 is operated to generate a first mute switch control data element indicative of the mute-off state of the first mute switch 71.
Similarly, the second mute switch control means 25 is operated to mute the audio signal inputted by the first mute switch control means 24 and output the muted audio signal to the third mute switch control means 26 when the second mute switch control data generating means 28 is operated to generate a second mute switch control data element indicative of the mute-on state of the second mute switch 72. The second mute switch control means 25 is operated to unmute the audio signal inputted by the first mute switch control means 24 and output the audio signal to the third mute switch control means 26 when the second mute switch control data generating means 28 is operated to generate a second mute switch control data element indicative of the mute-off state of the second mute switch 72.
The third mute switch control means 26 is operated to mute the audio signal inputted by the second mute switch control means 25 and output the muted audio signal to the output terminal 2 when the third mute switch control data generating means 29 is operated to generate a third mute switch control data element indicative of the mute-on state of the third mute switch 73. The third mute switch control means 26 is operated to unmute the audio signal inputted by the second mute switch 73 and output the audio signal to the output terminal 2 when the third mute switch control data generating means 29 is operated to generate a third mute switch control data element indicative of the mute-off state of the third mute switch 73.
The conventional mute apparatus 900 thus constructed is operated to selectively control the mute switch control means 24, 25 and 26 on the basis of the mute switch control data elements indicative of the operation states of the respective mute switches 71, 72, and 73 generated by the respective mute switch control data generating means 27, 28, and 29.
The conventional mute apparatus 900, however, encounters such a problem that one unit of mute switch control means is needed to process one mute switch control data element, i.e., to control one mute switch. This means that three units of mute switch control means are needed to control three mute switches. This leads to the fact that the “N” units of mute switch control data generating means must be provided to control the “N” units of mute switches. The mute switch control means is generally constructed by hardware. This leads to the fact that the “N” units of the mute switch control means must be provided by hardware, thereby increasing the size and cost of the mute apparatus.